Elementary particles Definition and 6 Discussions

In particle physics, an elementary particle or fundamental particle is a subatomic particle with no (currently known) substructure, i.e. it is not composed of other particles. Particles currently thought to be elementary include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are "matter particles" and "antimatter particles", as well as the fundamental bosons (gauge bosons and the Higgs boson), which generally are "force particles" that mediate interactions among fermions. A particle containing two or more elementary particles is called a composite particle.
Ordinary matter is composed of atoms, once presumed to be elementary particles—atomos meaning "unable to be cut" in Greek—although the atom's existence remained controversial until about 1905, as some leading physicists regarded molecules as mathematical illusions, and matter as ultimately composed of energy. Subatomic constituents of the atom were first identified in the early 1930s; the electron and the proton, along with the photon, the particle of electromagnetic radiation. At that time, the recent advent of quantum mechanics was radically altering the conception of particles, as a single particle could seemingly span a field as would a wave, a paradox still eluding satisfactory explanation.Via quantum theory, protons and neutrons were found to contain quarks – up quarks and down quarks – now considered elementary particles. And within a molecule, the electron's three degrees of freedom (charge, spin, orbital) can separate via the wavefunction into three quasiparticles (holon, spinon, and orbiton). Yet a free electron – one which is not orbiting an atomic nucleus and hence lacks orbital motion – appears unsplittable and remains regarded as an elementary particle.Around 1980, an elementary particle's status as indeed elementary – an ultimate constituent of substance – was mostly discarded for a more practical outlook, embodied in particle physics' Standard Model, what's known as science's most experimentally successful theory. Many elaborations upon and theories beyond the Standard Model, including the popular supersymmetry, double the number of elementary particles by hypothesizing that each known particle associates with a "shadow" partner far more massive, although all such superpartners remain undiscovered. Meanwhile, an elementary boson mediating gravitation – the graviton – remains hypothetical. Also, as hypotheses indicate, spacetime is probably quantized, so there most likely exist "atoms" of space and time themselves.

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  1. W

    B Electrons, quarks and gluons made from something or nothing?

    Most articles said electrons, quarks and gluons are indivisible thus have no compositions unlike the other particles. So, does that means electrons, quarks and gluons are composed of nothing and these elementary particles are indeed 100% void?
  2. W

    B Are these actually real electrons?

    I'm curious whether the scientists actually show the real electron in this video. Thoughts?
  3. kmm

    Particle Is Griffiths Introduction to Elementary Particles up to date?

    I have a copy of Griffiths Introduction to Elementary Particles (1st Edition) and was thinking of beginning to work through it. I was curious if anyone knows if this text is sufficiently up to date or if there have been any major developments in particle physics that would make it worth getting...
  4. jgarrel

    Quantum Field Theory-Mass spectrum of Lagrangian

    Homework Statement We are given the Lagrangian density: $$ \mathcal{L}=\partial^\mu \phi ^* \partial_\mu \phi - m\phi^* \phi +\sum_{\alpha =1} ^2 ( \overline{\psi}^\alpha (i\gamma^\mu \partial_\mu -m)\psi^\alpha -g\overline{\psi}^\alpha\psi^\alpha \phi^* \phi) $$ , where ##\phi## is a complex...
  5. LeInvertedPenguine

    I How elementary particles form matter

    Hello, So i wonder how elementary particles which are said to have no physical extension on a larger scale are able to form what is known to us as matter? Aka stuff with an observable physical extension.
  6. A

    Teaching particle physics in basic education

    Hi guys! I'm doing a research about teaching elementary particles in the middle school, something that isn't the reality in my country. Despite of the research in Physics Teaching be a lot advanced, the proposals made by them are not applied in the practice of the teachers. I want to propose...